SB-1 Defiant Opens Flight Envelope To 232 Knots

Compound helicopter
SB-1 Defiant
Credit: Photo credit: Sikorsky/Boeing

The Sikorsky-Boeing Defiant on Oct. 12 completed a flight test that expanded the rotorcraft’s flight envelope to 211 kt. in straight flight and 232 kt. in a descent, the companies announced. 

The new speed level by this coaxial-compound rotor with a pusher propeller was achieved at about two-thirds prop torque and engine power, according to a Lockheed statement. 

“We are excited about the results we are seeing and what the future holds for our ability to bring this capability to the warfighter,” the companies said in a statement. 

The Defiant, also known as SB-1, is the Lockheed-Boeing bid for the U.S. Army’s Future Long-Range Assault Aircraft and the Marine Corps’ Attack Utility Replacement Aircraft. The team is competing against the Bell V-280 tiltrotor for the contract. 

In June, Lockheed announced that the SB-1 had achieved a top speed of 205 kt. during flight tests.

Steve Trimble

Steve covers military aviation, missiles and space for the Aviation Week Network, based in Washington DC.